Explosion safety door for combustion chambers



Nov. 7, 1933. A. MAccHl EXPLOSION SAFETY DOOR FOR COMBUSTIKON CHAMBERS Filed Aug His Atto-#heg the pressure within the combustion chamber.

latented Nov. '7, 1933 UNITED STATES EXPLOSION SAFETY DOOR FOR COMBUS- TION CHAMBERS Aldo Macchi, Schenectady, N. Y., assignor to General Electric Company, a corporation of New York Application August 14, 1931. Serial No. 557,117

87C1aims.V (Cl. 110--173) My invention relates to improvements in 'heat-V ing apparatus, more particularly to improvements in explosion safety doors for combustion chambers.

Oil burner furnaces are subject to occasional explosions within the combustion chamber, and therefore some means must be provided for permitting the explosion to spend itself without damaging the boiler', chimneys, or burner ap-- paratus. This is usually provided for by means of an explosion safety door which is normally biased to a closed position and which on the occurrence-of an explosion will respond to the increased pressure therein to open and thus relieve It is necessary to provide a door which'is light and can easily be opened and which is sturdy enough to withstand the shock of being suddenly opened andV closed. Such a door must provide a gas-tight seal so that during the operation of the burner, air leakage will not affect the combustion within the combustion chamber. It is, of course, necessary to heat insulate the door and to reduce the transfer of heat from the interior of the combustionV chamber to the outside of the door to a minimum. Means should be provided to carry away any heat which might nd its way to the exterior or the door. Another desirable feature of such a door is the ability to make the door and frame as aV unit to be fastened to the boiler.

Hence, it is an object of my invention to provide an explosion safety door and frame unit which is light and durable.

It is another object of my invention to provide an explosion safety door for a combustion `cham-V ber which provides an airtight seal.

A further object of my invention is to provide an explosion safety door for a combustion chamber which is self-cooled.

A still further object of my invention is to pro- Vide an explosion safety door for a combustion chamber which is heat-insulated and in which the heat-carrying sections are reduced to a minimum. n n

These and other objects will appear hereinafter.

Briey, the preferred embodiment of my invention includes a door frame whichv can be fastened to the side of the combustion chamber. The frame is provided with a knife edge and has attached thereto a pair of arms for pivotally supporting a door biased to closed position. The bias permits the door to automatically open suiiiciently to relieve the pressure within the combustion chamber if an explosion occurs therein and to' close after the explosion is spent. The door comprises a portion consisting of a pair of concentric spun disks having a groove therebetween in which the knife edge of the frame is engaged when the door is in closed position. A heat-insulating portion carrying a member supported in spaced relation from these disks supports heat-insulating material by means of lingers within the frame but in spaced relation therewith. The member pivoted to the frame for supporting the door supports the door at its center by means of a bolt passing through the center of the door. The member is recessed at opposite sides so that a beveled washer and nut cooperating with the bolt carried by the door will center the door when'the door Yis attached thereto. In this manner the door has Contact with the frame only along the knife edge, thereby decreasing the heat-conducting surface contact between the door and the frame. Due to the fact that the heat-insulating material is supported in spaced relation with respect to the disks and the frame, practically no heat is transferred through the heat-insulating material to the outside of the door. j Attached to the outside of the door is a cover carried in spaced relation to the door so that a natural draft of air passing between the door and the cover will carry away any heat which has found its way to the exterior of the door. A

Referring to the drawing, Fig. l shows a front View of my door 'for a combustion chamber; Fig. 85 2 shows a cross section thereof along the line 2 2 of Fig. 1; Fig. 3 shows a cross section of the door along the line 3 3 of Fig. l.

Referring speciiicaliy te the tirar/'ing in Fig. l and Fig. 2, theinner casing i0 of the combus- 90 tion chamber is previded with a heat-insulating cover l1 and an outside insulating cover 12. l Attached tothe door opening in the side of the combustion chamber the ring 4member 13. The door unit which is carried en the ringmember 14 bolted to the ,i3 by suitable bolts l5 comprises the'frame andthe door. A pair of arms 16 and 1'? welded to the ring 14 pivotally support upon the pin 18 extending therebetween the member .2G which supports the door and which is biased toward the frame by means of the spring 21. The frame is provided with the knife edge 14'.

The door is made up of several parts.y A cupshaped member 22 forms the innerpart of the door and has welded thereto the iingers` 23 which support the nre brick member 24 and the heatinsulating portion 25 comprising some light material Asuch'as asbestos to reduce the Weight of the door.

' and the cover.

Referring to Fig. 3, it will be seen that the door also comprises the two spun disk members 26 and 27 of different diameters which are concentrically mounted and provide between their edges or laterally extending flanges a groove which cooperates with the knife edge 14 of the door frame when the door is in closed position. A gasket 28 of heat-insulating material is provided in the groove to insure a tight joint which is leak-proof when the door is closed. A bolt member 34 carried by the cup portion 22 of the door extends outwardly and forms a support for the door upon the pivoted member 20. A Washer 29 held in place by means of the beveled nut 3l clamps the disk members and the cup-shaped member together. The supporting member720 is provided with an opening therethrough having recessed portions to engage the beveled nuts 31 and 32 which automatically centers the door when the door is fastened to the pivoted member 2 0. It will be noted that the door is mounted in spaced relation with the member 20. It will thus be seen that the conducting surfaces are very small since contact with the combustion chamber walls is found only at the knife edge of the door frame and contact with the inner portion of the door is found only in the bolt for supporting the door upon the pivoted member 20. Thus the heat transfer by conduction from the inner face of the door within the combustion chamber to the outside of the door formed by the disks l26 and 27 is reduced to a minimum.

'To further insure that the door remain cool during combustion Yconditions within the combustion chamber, a cover 33 is `supported upon the pivoted member 20 by means of the pillars 35 and the cooperating screws. It will be seen that this cover is mounted in spaced relation with respect to the door and that a natural draft will take placeV from top to bottom betweenthe door This natural draft of air will carry away any heat that has found its way to the outside of the door by conduction or radiation from the combustion chamber.

Thus it will be seen that I have provided a door 5 and frame which can be mounted as a unit upon a combustion chamber. It will also be seen that my door is sturdy, light, provides a gas tight seal for the combustion chamber, is self-closing, selfcooled, and dueto its unique construction ref ducesthe heat conduction from the interior of the combustion chamber to the exterior of the door to a minimum.

In accordance with the provisions of the patent statutes I have described the method of operation'of my invention, together with the apparatus which I now consider torepresent the best embodiment thereof, but I desire to have it understood that theapparatus shown is only illustrative'and that the invention may be carried out by other means.

`What I claim as new and desire to secure by Letters Patent of the United States, iszl. A door unit for a combustion chamber including a door frame to kbe fastenedto said combustion chamber, and a door for engaging said frame for forming a' gas tight fitting when closed on said frame, a refractory supported by said door on the inside thereof at one point thereon in spaced relation with said door, and a cover l for the outside of said door mounted in spaced relation therewith. at a different point from the point of support for said refractory.

2.. A door unit for a combustion chamber in cluding a door frame to be fastened to said` combustion chamber and provided with a knife edge and a door provided with a groove for cooperating with said knife edge for forming a gas tight joint therewith when in closed position, a refractory supported on the inside of said door in spaced relation with said door and centrally thereof at one point, and a cover for the outside of said door supported in spaced relation therewith at points spaced from the point of support for said refractory.

3`. An explosion safety door unit for a combustion chamber including a door frame to be fastened to said combustion chamber and provided with a knife edge, a door supported by said frame, means for biasing said door to closed position, said door having a pair of concentric spun disks having laterally projecting flanges and forming a groove therebetween for said knife edge when said door is closed for providing a gas tight tting between said door and said frame.

4.'4 An explosion safety door unit for a combustion chamber including a circular door frame having a'knife edge, a door supported by said frame having a pair of concentric spun disks of differentdiameters havinglaterally projecting flanges and forming a groove therebetween, said knife edge being engaged in said groove when said door is closed on said frame to provide a gas Vtight tting between saidrdoor and said frame.

5, A self cooling door for a combustion chamber comprising a door frame, a door cooperating therewith a memberA movably mounted on said frame and supporting" said door, aV refractoryv having a supporting element joined to ,the door at one point for supporting the refractory inY spaced relation with the door, a cover for the, exterior of said door, said cover being supported by said movably mounted memberL in spaced relation with respect to said door at different p oints than the point of support for said refractory, whereby a draft between said door and, coverwill cool said door and cover.

6. A door for a combustion chamber includ,- ing a door frame to be fastened to said combustion chamber, a heat insulated door cooperating with. said frame and forming a gas tight fitting therewith when in closed position, a

member movably mounted on said frame andV supporting said door at one point and in. spaced relation with said member elsewhereV and on one side thereof and a cover for the exteriorV of said door` carried by said memberon the other side fromv said door in spaced relation with said` member whereby a natural draft passing be'- tween said cover and door will maintain said cover and door cool during combustion within said combustion chamber.

7. An explosion' safety door unit for a com bustion chamber including a door frame to be fastened to said combustion chamber and provided with a knife edge, a pair of arms carried by said frame, a door having a groove for cooperating withsaid knife edgeY when said door is in closed position to forma gas tight joint, a member movably mounted between said arms, means lfor biasing said member toward said' frame, said door being supported at its center by said biasedjmember and provided with a` spacer for spacing said door'from said member, said center mounting causing the force of said bias tobe evenly` distributed between saidrknife edge and said door, whereby heat, conduction ifi() for supporting' said door at one point at its center whereby the heat transfer from the interior of the combustion chamber to the outside of said door is substantially reduced, and a cover carried by said member spaced from the outside of said door whereby a natural draft between said cover and said door will carry away any heat conducted to the exterior of the door from said combustion chamber.

ALDO MACCHI. 

